Swivel chair



Dec. l0, 1940. F. las.i HARMAN SWIVEL CHAIR Filed March 22, 1959 uw Uw x f. uw 2 5 2 y. n MH Pf 4K m Patented Dec. 1G, 1940 Unire isriires rATENr OFFICE SWIVEL CHAIR Frank B. Harman, Sturgis, Mich.

application Maren 2 2,

The object of this inventionis to providea swivel chair which may be manually adjusted to a proper elevation by a person sitting in the chair irrespective of the position of the seat portion relative to the base and whichmay be freely rotated without affecting the height of the seat.

In the accompanying drawing is an illustrative embodiment of this invention, wherein:

Figure l isan elevation of a swivel chair having the new supporting mechanism;y v

Figure 2 is an enlarged section taken on the line 2 2 of Fig. l;

Figure 3 is a vertical 3-3'of Fig. 2; and

Figure 4 is a fragmentarysection taken on the line 4-4 of Fig. 3.

section taken on theline A swivel chair following the design of this invention would include some suitable seat portion I0 to which may be joined a back The seat portion may be of any of the customary styles or may be a simple support having neither arms nor back. The seat H3, whether of the tilting or non-tilting type, is supported on a spindle I2, which, in the case of the non-tilting type herein shown, may be rigidly connected to the seat through a spider I3. rThe spindle may be keyed to or integral with the spider.

The spindle I2 is preferably steel and has a threaded portion I4 through which extends a longitudinal groove I5. This spindle is journaled in bearings I6 and I "l which are mounted in a base frame I8.

The base frame may be of wood, metal or any other suitable material and is preferably high enough so that the entire threaded portion |13 of the spindle I2 can pass through the bearings I6 and Il.

Upon the spindle l2, at a point between the base and the seat is located a mechanism 23 which serves the two-fold purpose of maintaining the .spindle I2 at a certain level in the base i3 and of permitting the level of the spindle in the base to be raised or lowered by a single manual control.

The mechanism 2B comprises a worm wheel 2| having internal threads 22 which cooperate with the threaded portion Iii of the spindle I2, a worm 23 which is meshed with the worin wheel 2|, and a manually operable shaft 2i upon which is keyed by set screw 25 the hub of the worm 23.

1939, serial' No. 263,343

(ci. 15s-93) A'housing 26 completely encloses the mechanism 20.

The housing 26 is preferably made of two metal stampings 21 and 23 having upper and lower fvertical bearings 29 and 30, respectively. The housing is carried by the worm wheel 2| and is maintained in a stable position on the worm wheel by having the spindle I2 extending through bearing 23 and having a hub 3| of the worm wheel 2| extending through the bearing 33. The hous- 10,`

ing is slidably keyed to the spindle I2 by a key 32 which is cut out of the bearing 29 and which engages the longitudinal groove I5 of the spindle I2.

Rotatably supported by the housing 25 at bear- 15 ing' points 33 and 34 is the shaft 24. The shaft is secured against endwisemovement by the screw 25 and the bearing of the Worm hub on the adjacent side wall of the housing and by the insertionl of a spacer sleeve 35 between the bearing 20 point 34 and the worin 23. On one end of the shaft is fixed a hand Wheel S for manually rotating the shaft. The handle 36 is placed on an end of the shaft which is suiciently extended so that the wheel may be conveniently operated 25 by any person sitting in the chair.

The worm wheel 2| supports the spindle I2 in the base I8 by the abutment of the lower end of its hub on the bearing I3. The position of the worm wheel on the spindle determines the height of the seat. The worm wheel cannot turn on the spindle under the weight of the occupant of the chair because it is locked against such turning by the worm, and the housing in which the worm is JOurnaled is locked against turning f on the spindle by the key 32. The seat may be freely rotated relatively tothe base without altering the elevation of the seat, since at such time the spindle, worm gear, Worm and housing are all locked against vrelative rotation but rotate 40 t With the seat; the hub 3| of the worm wheel 2| sliding over the top face 3l of the bearing I6.

To operate the mechanism 2B in order to change the elevation` of the seat I0, a person seated in the chair need only to reach beneath that portion of the seat where the handle 36 will always be found, turn the shaft 24 by means of handle 36 which will in turn rotate the worm 23 and thus the worin wheel 2|. The rotation of the worm wheel will cause the spindle I2 which is `ISO keyed to the housing 26 and thereby indirectly. to the shaft 24 to move up or down depending on which way shaft 24 is turned rather than rotate. This vertical movement will-be relative to the mechanism 20 which continuously abuts 65 upon the base I8 and, therefore, will result inl a change of the elevation of the seat portion I0. When elevating the spindle, the down thrust of the worm wheel 2l is opposed by the bearing I6. When lowering the spindle the up thrust of the worm wheel is opposed by the weight of the seat or the occupant of the seat acting on the worm Wheel through the spindle, the worm wheel acting at such time merely as a regulator of the down movement of the spindle. The gear ratio between the worm 23 and the worm Wheel 2| will determine the effort and the speed with which any adjustment can be made. ing arrangements than that described (e. g. two bevel gears) may also serve in the mechanism.

vHaving the handle 36 keyed indirectly through the housing 26 to the spindle I2 makes possible the feature of having the handle always inthe same position relative to the seat l irrespective of the position of the seat with respect to the base.

I claim:

1. In a chair of the type described, the combination of a base structure having a vertical spindle guide, a seat, a vertical spindle at its upper end secured to and ,supporting saidseat, said spindle having a threaded portion slidably engaged with said spindle guide, a worm wheel having an internally threaded hub engaged With the threaded portion of said spindle and at its lower end stepped on said spindle guide, a housing encircling said spindle and enclosing said worm wheel, means rendering said housing non-rotatable relatively to said spindle but permitting vertical travel of the latter through said housing, a shaft journaled in opposite Walls of said housing, a`y worm fast on saidr shaft engaged with said worm wheel, and a hand wheel on said shaft.

' 2. In a chair of the type described, the combination of a base structure having a vertical spindle guide, a seat, a vertical spindle at its Other gearupper end secured to and supporting said seat, said spindle having a threaded portion slidably engaged with said spindle guide and a longitudinal groove, a worm Wheel having an internally threaded hub engaged with the threaded portion of said spindle and at itslower end stepped on the upper end of said spindle guide, a housing encircling said spindle and enclosing said worm wheel, said housing having a key in sliding engagement with said longitudinal groove of the spindle and a vertical bearing encircling said hub,.a horizontal shaft journaled in opposite side Walls of said housing, a worm fast on said shaft engaged with said worm wheel, and a hand Wheel on one end of said shaft.

, 3. In a chair of the type described, the combination of a base structure having a vertical spindle guide, a seat, a vertical spindle at its upper end secured to and supporting said seat, said Vspindle having a threaded portion slidably engaged with said spindle guide and a longitudinal groove, a worm Wheel having an internally threaded hub engaged with the threaded portion of said spindle and at its lower end stepped on the upper end of said spindle guide, a housing encircling said spindle and enclosing said worm wheel, said housing having a key in sliding engagement with said longitudinal groove of the spindle and upper and lower vertical bearings, said upper bearing encircling the spindle with its lower end bearing on the upper face of the worm wheel and said lower bearing encircling the hub of the worm wheel with its upper end bearing the lower face of the worm wheel, whereby said housing is locked against vertical displacement relatively to the worm wheel, a horizontal shaft journaled in opposite side walls of said housing, a worm fast on said shaft engaged with said worm wheel, and a hand wheel on one end of said shaft.

' FRANKB. HARMAN. 

